A passive optical network (PON) is a point to point optical access technology. A PON includes an optical line terminal (OLT), an optical splitter, an ONU and an optical fiber connecting these devices. The OLT is connected to an optical splitter by using a backbone optical fiber, and the optical splitter is connected to ONUs respectively by using multiple branch optical fibers.
To ensure that services can still be performed normally when a fault occurs on the OLT, two OLTs may be used for backup. FIG. 1 is a schematic structural diagram of OLTs and ONUs in the prior art. In FIG. 1, a first OLT1 and a second OLT2 each are connected to an optical splitter 3 by using an independent backbone optical fiber. The optical splitter 3 is connected to each ONU4 by using a branch fiber. The first OLT1 and the second OLT2 both communicate with an element management system (EMS) 5. In normal cases, the first OLT1 communicates with each ONU4. When detecting that a fault occurs on the first OLT1, the EMS5 instructs the second OLT2 to serve as a master OLT and transmits synchronization data of the first OLT1 to the second OLT2 so that the second OLT2 communicates with each ONU. The synchronization data refers to all types of data needed for communication between the second OLT2 and each ONU, for example, an identification of each ONU (ONU ID), and a serial number of each ONU.
The data synchronization method in the prior art has the following problems: each OLT communicates with the EMS based on the Simple Network Management Protocol (SNMP), and the speed of data transmission is slow; and each OLT and the EMS are far from each other physically, and interaction data may need to span multiple switch devices. If a fault occurs on one of the switch devices, the communication between the OLT and the EMS cannot be performed, resulting in that data synchronization cannot be implemented. As a result, the reliability of the data synchronization method is not high.